Soap can be made from fats and oils, sodium hydroxide, and water. Soapmaking can be as simple as dissolving sodium hydroxide in water, melting fats together, adding the sodium hydroxide solution (lye) to the melted fats, and stirring. It can get more complicated, but it needn’t. This book starts at the beginning, assuming the reader knows nothing about soap-making. Chemistry is discussed, but in digestible portions and only enough to get a good working feel for the observable process. I survived high school chemistry only with the help of a motivated friend. I am well aware that those kinds of friends and that kind of motivation are not so common anymore for me and my post-teenage readers. Accordingly, this book has been written sympathetically, for the reader who does not have an interpreter. The chapters are arranged to take you step-by-step up to, through, and beyond the soapmaking process.
Part One introduces you to six different ways of classifying soaps. Part Two describes, in detail, the many soapmaking ingredients. Part Three explains how to make soap, from choosing the equipment to cutting and trimming the final bars.
In Part Four, I take you “Beyond the Basics,” to encourage creativity in wrapping and presenting your soaps. I also provide a more detailed discussion of the chemistry of soapmaking, reminding the reader to rejoice that soapmaking is more art than science.
Scattered throughout this book, you will find the stories of a handful of commercially successful American soapmakers who share their experience and trace their journeys through soapmaking.
The appendices include a list of suppliers from whom you can buy soapmaking ingredients, a glossary, and a list of related reading material.
Chemically — and I’ll explain this in detail later — soap is a salt. An acid and a base react with one another and neutralize into the salt (or soap). This process is called saponification; as the acid and the base come into contact with one another and react, the solution is saponifying — making soap. There are many forms of acids and bases and many different ways of making soap. One method relies upon sodium hydroxide for the base, another sodium carbonate, and yet another potassium hydroxide. One method uses fats and oils for the acid, another just the pure fatty acids already split from the fat. One method releases glycerin, another doesn’t. One involves boiling the soap in commercial kettles that hold several hundred thousand pounds, another is made in a small pan on your kitchen counter.
All of these methods produce soap, but most are beyond the scope of this book and the interest of humankind. Homemade bars are manufactured with fats and oils (the acid), sodium hydroxide (the base), and water (the solvent which dissolves the base). Making soap with easily accessible materials, without complex chemical additives, and using only the heat of the reaction (no external heat), is called the cold-process method. This book is about making soap most simply — using fats and oils, sodium hydroxide, and the cold-process method.
The same cold-process method used to make animal-based (tallow or lard) soaps can be used to make all-vegetable soaps. Though some soapmaking manuals include vegetable formulas, they fail to explain that making vegetable soaps requires some adjustments.
While the basic method remains the same, slight variations in the temperament of each vegetable oil call for special attention. Vegetable oils cannot tolerate the high temperatures that animal tallow can withstand, require different amounts of sodium hydroxide, can take longer to saponify (make soap), require different preservatives, and cure differently as soaps. Formulas incorporating a high percentage of beef tallow can be made at higher temperatures. When vegetable soaps are made at high temperatures, the mixture curdles more easily, produces a grainier soap, and has a tough time incorporating the essential oils.
The soapmaker who is interested in researching tallow/lard-based soaps has plenty of existing material to read; this book emphasizes vegetable-based soaps and their individual characteristics and complexities.
Once you understand basic soapmaking chemistry, and which laws must be followed and which ones can be defied, then you can play with the formulas. There is no one right way to make soap, but I will guide you to successful soapmaking.
Before focusing too narrowly on the details of soapmaking, it is worth pausing for a moment to understand how soap works. To clean skin or fabric, something must make the surface wet and attract the dirt away. Soap does both.
THE DISCOVERY OF SOAP
The story told in 1,000 B.C. Rome, about the discovery of soap on Sapo Hill, has been repeated so often that mythical elements have taken on factual proportions.
The story tells of women rinsing clothes in the river at the base of a hill, below a higher elevation where animal sacrifice had taken place. They noticed the clothes coming clean as they came in contact with the soapy clay oozing down the hill and into the water. They later discovered that this cleansing substance was formed when the rendered animal fat soaked down through the wood ashes and into the clay soil.
Ironically, water alone does not wet well. Water molecules are closely bonded and resist being broken apart. They bead up on the surface and do not spread out easily. Soap acts as a surfactant, or a surface active agent, which means that it helps the water to soak in rather than form tight droplets. Soap molecules have heads which attract water, and tails which repel it. When mixed with water, these soap molecules push their hydrophobic tails up through the surface of the water, to get as far away as possible. All of these tails poking through the top layer break up the surface tension of the water and cause it to spread out and wet more thoroughly.
Soap removes dirt and grease in two stages. First, it attaches itself to the dirt, and then it suspends the dirt in lather until a rinse carries them both away. More specifically, a soap molecule is a chain of atoms — including carbon, hydrogen, and oxygen — arranged with a distinct head and tail. The head is attracted to water, the tail to dirt. The soap molecule cleans by embedding its tail into the dirt and dislodging it as its head pulls toward the water. The soap then holds the dirt in suspension until it’s rinsed away.
